Editorial for Mock CCC '22 1 S1 - Big Mattress Tournament
Submitting an official solution before solving the problem yourself is a bannable offence.
For 14 marks, one can recursively pair up tiles that form mattresses and brute force those to see if other ones can be constructed.
For full marks, it suffices to verify that the number of tiles is even, there are at least as many tiles as
L tiles, and either there are an even number of tiles or at least one tile.